Automatic firearm



H. J. UPPER-r AUTOMATIC FIREARM Feb. 27, 1945.

Filed July 27, 1939 2 SheeLS-Shevfrl 1 RQ f Feb. 27, 1945. H, J. UPPERT 2,370,363

AUTOMAT IC FIREARM Filed July 27, 1939 2 Sheets-Sheet 2 TToR/VE Ys l Patented Feb. 27, 1945 AUTOMATIC FIREARM Hans Julius Lippert, Zurich, Switzerland Application July 27, 1939, Serial No. 286.787 In Switzerland August 1, 1938 (Cl. 89-3l 8 Claims.

The requirements which modern warfare makes of automatic arms, particularly machine guns, aim first at increasing the rate of re as much as possible and secondly at securing the highest possible capacity for withstanding continuity of re. Both the increase in the performance by increasing the rate of fire and also the withstanding of rather long and continuous re tests, represent when considered individually an increased stress on the fire-arm. A combination of continuity of tire and an increase in the rate of fire very decidedly involves an increase in the stress.

Mechanically rigidly locked systems in the form of recoil-operated guns with barrel recoil or of gas-operated guns enable the rate of fire to be increased very considerably by a suitable choice of mechanism. A disadvantage which then immediately appears is the fact already quite general with Athese systems that the more or less complicated mechanism required for the mechanically rigid locking, in so far as it can be rendered serviceable for a high rate of fire, has a tendency to produce stoppages and is by no means equal to long duration of re.

The systemof mass locking, which on account of the absence of any mechanical locking means is very simple and therefore extremely robust has proved itself equal to continuous firing tests in In this system. "3

a very outstanding manner. however, the possibility of military application very soon sets/a limit to an increase in the rate of lire for simple reasons. Thus, for example, in the case of an automatic gun of this type with a calibre of 40 mm. a rate of lire of 200 shots per minute would have to be obtained at the expense of a recuperator spring, the tension of which amounts to '700-800 kg. and the corresponding breech block mass would have to have a weight of 130 kg.

If it was desired to fire a gun of this type with a calibre of 20 mm. at a rate of fire of 800 shots per minute, it would be necessary to drive a breech block mass weight of 8 kg. bymeans of spring, the tensioning force of which amoun to 5D0 kg. gun in the open country, the precision and also the manufacture of springs, it is obvious that such masses, forces and the energies rof motion the permissible degree. f f,

To sum up, it may be said that with/ rigidly locked fire-arms, higherrates of remay be attained than heretofore, but they are not equal to long continuity of lire. On the other hand,

In view of setting up the produced at the indicated frequencies'far exceed 5 the mass-locked fire-arms withstand long continuity of nre but their rate of re is limited.

The present invention satises both requirements by employing a novel locking system, which makes it possible to effect locking in the same way as in the mass-locking method without mechanical locking means, while at the same time permitting the application of small, rapidly movable breech block masses with recuperator springs of low tension.

This isaccomplished in accordance with the invention by uniting the breech block mass with the mass of the barrel through a hydraulic resistance which permits relative movement between the breech block and barrel during the action of the gas pressure forces in order to absorb such forces. Consequently, even with rather large calibres, a small, rapidly movable breech block mass can be used, and in spite of this, the gas forces can' be taken up by coupling the itself insufl'icient breech block mass with the mass of the barrel.

The invention will be further described in detail with the aid of the accompanying drawings which show by Way of example an embodiment of the invention. In said drawings,

Fig. 1 is a vertical section through the automatic gun along the longitudinal axis of the barrel;

Fig. 2 represents a horizontal section;

Fig. 3 is a transverse section along the line II-II of Fig. 2; while Figs. 4 and 5 show the parts in different positions.

The barrel of the gun is shown at I, and is supported within the casing 3, in which is disposed the breech sleeve 2 connected to the barrel. Within the sleeve 2 the breech block 4 and the recuperator spring 5 are longitudinally guided. The barrel, however, is not rigid with the casing 3 as is usual, but slides in the casing 3 along with the breech sleeve 2 connected therewith. The recuperator spring E urges the barrel with the breech sleeve 2 against the stop or abutment 3d. The casing 3 is rigidly connected with the gun mount l5 at the extension 3c by means of the bolts I6. The cartridge magazine is shown at 9.

Connected with the breech block 4 by way of the connecting bar 8 and the rods I0 are pistons II which move in the bores of the two brake cylinders l. The pistons II are provided each with a non-return valve I2 pressed against their seats by the springs I3. The pistons II are further provided with through channels IIa controlled by the valve I2, and also with slits IIb in the valveseatleadingfromtheehannala 'ilabutnot citrolled by the valves. The lll'ahev cylinders are filled with a suitable liquid indicated at Il.

'Ihecylindersareeachprovidedwithatransi'er passage'lbconnectedatitsrearwiththe rear portion of the cylinder but connected at its front end at a point removed from the forward end of the cylinder. By this construction the piston acts as a slide valve covering the forward connection between the cylinder and transfer passage,aswillbeseenfromFigs.4and; during the initial rearward movement of the pistons. as shown in Fig. 4. flow of huid through the transfer passages is prevented until the pistons have uncovered the forward connections between the cylinders and transfer passages. During this inter' val, iluid is transferred from the rearward to the forward portions of the cylinders only through the slits lib. Upon forward movement of the' pistons into the forward extensions 'lo of the cylinders, the displaced duid can escape only through the passages Ila and lib and against the action of the springs Il so that a resistance is opposed to the forward movement of the pistons The operation of the illustrated fire-arm is as follows: Prom the open breech position. as shown in Figures l and 2, the breech block is projected forwardly by the recuperator spring I. 'Ihe two pistons il move the liquid il rearwardly through the transfer passages 1b. During the whole of the forward stroke, the barrel and breech sleeve .s in their moet advanced position are pressed against the stop Id by the recuperator springs l. When the pistons Il close the forward transfer opening. the hydraulic coupling comes into operation, the liquid being able to escape only through channels iid and valve I2, until the forward reversing position shown in Figure 4 has been reached. In this way. the forces transmitted by the hydraulic coupling are transmitted directly to the gun mount Il through the stop Id. mi the following recoil stroke of the breech block. the action of the hydraulic coupling is still further increased to a considerable degree, because the valves i! are pressed against their seats by the liquid pressure produced and only allow the liquid to pass through the slits lib. The rearward driving force of the gas pressure babsorbedbythebreechblockandistransmitted through the hydraulic coupling partly also to the barrel I and the breech sleeve 2, which underthisiniluenceslideinthecasingsand movebackwardasainsttheactionofthe reeuperator springs l. Prom the operation debreech block with said barre1 for retardlhg relative movement therebetween upon firing, whereby the additional inertia of the movable barrel is utilized to resist the action of the gases.

2. An automatic fire-arm according to claim l. wherein the hydraulic coupling means comprises a liquid-filled cylinder connected to the barrel.

-a piston movable in the cylinder and connected to the breech block. and means for controlling the flow of the liquid in the cylinder in a manner to cause coupling of the breech block with the barrel approximately from the moment of firing to shortLv before the cessation of the las pressure forces.

3. An automatic fire-arm comprising a casing. a barrel slidable in said casing. a slidable breech block, a liquid filled cylinder rigidly connected with the barrel, a piston slidable in said cylinder and connected with the breech block, and means acting to create a resistance to the movement of as the piston within the cylinder during the initial rearward movement of the breech block to compel the cylinder and barrel to move with the breech block, whereby the masses of the breech block. cylinder and barrel are coupled for absorbing the forces created by the gas pressures.

scrbed above it follows that the breech block, i

during the coupling, is driven more rapidly to the rearby the amoimt of the slippage between the breech block and barrel. The hydraulic coupling is automatically rendered inoperative by the front face of the pistons uncovering the transfer passages 1b. At this moment, the gas pressure has not yet entirely ceased to act.A so thataresidualgasimpulseactson thebreech block alone and drives it into its rear reversing pdtion. After the coupling has been rendered menthe. the barrel l and the breech sleeve i are ilmediately forced forward again by .s recuperatorspringst. 'Iheywillreachtheir'lil' wardposition ofrestbeforethebreechupaies tbrouh its rear reversing position lhsmthsstandpointofthelocking, the brief ooopiiagofUr/breeehbloekwithizemovable barrelandbreech sleeveshiiiiesanimreasein WWMNMMMMM il H 4. An automatic fire-arm comprising a casing.

a barrel slidable in said casing. a slidable breech l block, a liquid filled cylinder rigidly connected with the barrel. a piston slidable in said cylinder and connected with the breech block, and means acting to create a resistance to the movement of the piston within the cylinder during the initia rearward movement of the breech block to compel the cylinder and barrel to move with the breech block. whereby the vmasses of the breech block, cylinder and barrel are coupled for absorbing the forces created by the gas pressures. said cylinder including a transfer passage for the liquid from the forward to the rearward part of the cylinder and vice versa. the forward connection between the cylinder and passage being spaced from the forward end of the cylinder. whereby the piston closes such connection in its forward position, said means including a channel in the piston limiting the movement of fluid from the rear to the forward portions of. the cylinder during the period that the piston covers the said cylinder including a transfer passage for the liquid from the forward to the rearward part of the cylinder and vice versa, the forward connection between the cylinder and passage being spaced from the forward end of the cylinder, whereby the piston closes such connection in its forward position, said means including a channel in the piston limiting the movement of fluid from the rear to the forward portions of the cylinder during the period that the piston covers the said connection in its rearward movement, and a nonreturn valve arranged to partially close said channel and to be unseated during the forward movement of the piston.

6. An automatic fire-arm of the mass-locked type, comprising a casing, a barrel slidable therein, a slidable breech block, a hydraulic coupling having parts connected to the barrel and breech block, said coupling including means whereby said coupling connects the barrel and breech block to cause the two to move together during the initial rearward, recoil movement of the block, subsequently effective means for substantially releasing the connection between the barrel and block, and mechanism for returning the barrel and breech block to iiring position.

'7. An automatic fire-arm, comprising a casing, a barrel and a breech block both slidable in said casing, the barrel being slidable rearwardly from the ring position, a recoil spring acting on the barrel and urging it forwardly to ring position, an automatic hydraulic coupling between the breech block and barrel and acting upon the explosion of a projectile charge to couple the mass of the barrel to that of the breech block, the inertia of the breech block barrel and coupling constituting the only initial resistance to the rearward movementI of the breech block, the hydraulic coupling being provided with means for gradually releasing the interlock 'between the breech block and barrel, whereby relative movement ltherebetween occurs as the breech block recedes further from ring position, and recoil mechanism for returning the breech block to ring position.

8. An automatic fire-arm, comprising a casing, a barrel and a breech block slidable in said casing, the' barrel being slidable rearwardly from firing position, recoil mechanism for returning the barrel and breech block to firing position, and mechanism for utilizing the inertia of the breech block and of the barrel for initially and temporarily resisting recoil movement of the breech block, saidmechanism comprising a pair of hydraulic cylinders connected with the barrel, pistons in said cylinders connected with the breech block, means in said cylinders interposing a high resistance to the flow of liquid from the rear to the forward portions of the cylinders, means in said cylinders affording a low resistance path for the liquid after the pistons have travelled a limited distance, whereupon rapid relative movement betweemthe breech block and barrel takes place, said cylinders providing a low resistance path for liquid from the forward to the rearward portions of the cylinder upon forward travel of the pistons.

HANS J ULIUS LIPPERT. 

